Here's why, most companies/organizations take advantage of passionate employees who're engrossed in their work. Don't be one of them.

The old expression of 'do what you love' was when companies respected their crew and vice versa. Today, that social contract is out the window. Also, don't fall for the one or two 'special companies' which pretend to be different. Once they're bought/sold to a new management, the same story will replay itself.

Find hobbies and get engrossed in them; then find work which gives you a balance and then you'll be happy and can have the time to do what you love. Obviously, if you're a big sales closer or commodities trader than you'll have even more money for your passions outside of work, however, even a regular worker can find paid work where the clock stops at the 40 or 42 hour mark and doesn't have implicit overtime rules. (*Hint: don't work for big law firms unless you're going to be made partner)